1. Field of the Invention
The present invention relates to pressure adjuster valves, and more particularly to a pressure adjuster valve in which when chamber pressures within the two chambers are reversed, the chamber pressures may be quickly and positively caused to be equal to each other. The present invention also relates to a gas compressor utilizing the pressure adjuster valve.
2. Description of the Related Art
FIG. 6 shows a gas compressor for an automotive air conditioning system. In the same drawing, the gas compressor incorporates therein a pressure adjuster valve 50 as means for preventing the reverse phenomenon of chamber pressures between a suction chamber 11 and a back pressure chamber 23.
That is, in case of the gas compressor shown in FIG. 6, since, upon the operation thereof, the low pressure refrigerant gas within the suction chamber 11 is compressed with in a cylinder 1 and discharged to the side of a discharge chamber 19 as high pressure refrigerant gas, comparing the suction chamber 11 and the back pressure chamber 23, the suction chamber 11 is lower in chamber pressure than the other chamber. However, in the case where a vehicle is parked for a long period of time at a standstill state in particular under the sunshine in high summer and the like, since the refrigerant gas is soluble in the oil within an evaporator constituting the air conditioning system, the refrigerant gas contained in the oil is warmed by an external air kept at a high temperature and gasified and introduced into the suction chamber 11 side of the gas compressor and the like, under the standstill state before starting the gas compressor, the phenomenon that the chamber pressure within the suction chamber 11 is higher than the chamber pressure within the back pressure chamber 23, i.e., the so-called reverse phenomenon would occur.
Moreover, in case of a vane rotary type gas compressor as shown in FIG. 7, the compression of refrigerant gas is performed by the volume change of a compression chamber 10 inside the cylinder 1. Also, the pressure of refrigerant gas to be sucked into the cylinder 1 from the suction chamber 11 is applied to work on the tip ends of vanes 9 forming and partitioning the compression chamber 10.
Accordingly, in accordance with the gas compressor with the structure shown in FIG. 6, under the standstill state before the start of the operation, the pressures of the suction chamber 11 and the back pressure chamber 23 are reversed as described above. For this reason, the vanes 9 are pressed back to vane grooves 8 of a rotor 4 by means of the pressure of refrigerant gas within the suction chamber 11. Therefore, upon the start of the operation, the sealability of the compression chamber 10 partitioned and formed by the vanes 9 and the like is lost, and the compression function of refrigerant gas by the volume change of the compression chamber 10 is degraded, disadvantageously.
Therefore, in the gas compressor shown in FIG. 6, the discharge chamber 19 and the back pressure chamber 23 are in communication with each other through an oil feed passage composed of an oil hole 21, clearances of bearings 5 and 6 and the like. Accordingly, the pressure adjuster valve 50 is provided between the back pressure chamber 23 and the suction chamber 11 as shown in FIG. 8 so that the reverse phenomenon of the chamber pressures between the back pressure chamber 23 and the suction chamber 11 is prevented.
In case of the pressure adjuster valve 50 shown in FIG. 8, when the chamber pressure of the suction chamber 11 is lower than the chamber pressure of the back pressure chamber 23, a valve body 55 is pressed into a truncated conical hole 52 by means of the pressure difference between the two chambers 11 and 23 to close a communication passage 51. On the other hand, when the chamber pressures of the two chambers 11 and 23 are reversed, the valve body 55 is released and moved away from the truncated conical hole 52 by means of the pressure difference of the two chambers 11 and 23. Thus, the pressure of the suction chamber 11 is released to the side of the back pressure chamber 23 through the communication passage 51 and the chamber pressure of the suction chamber 11 is caused to be equal to the chamber pressure of the back pressure chamber 23.
However, in accordance with the pressure adjuster valve 50 with the conventional structure shown in FIG. 8, a gap portion 57 between an edge portion of the truncated conical hole 52 and a surface facing the edge portion is present and the valve body 55 that has been rolled and dropped from the truncated conical hole 52 is partially engaged with this gap portion 57. Accordingly, even if the chamber pressure of the back pressure chamber 23 is higher than the chamber pressure of the suction chamber 11, the valve body 55 hardly would be returned in the direction toward the truncated conical hole 52. Thus, there is a problem that a smooth opening/closing operation of the communication passage 51 could not be ensured.
In order to solve the above-described problem of the pressure adjuster valve 50 shown in FIG. 8, there has been an approach that a front portion from the truncated conical hole 52 is formed to extend in the form of a cylinder as the means for eliminating the gap portion 57. However, in the structure according to this approach, in the case where the oil for lubricating the compressor for lubrication during the operation of the compressor is left within the communication passage 51 even after the standstill of the compressor, an oil film is formed around the valve body 55 so that the valve body 55 is kept stuck to the truncated conical hole 52 by this oil film, or even if the valve body 55 is separated away from the truncated conical hole 52, in some cases, the communication passage 51 is closed by means of the oil film and the normal function of the pressure adjuster valve 50 is lost. For this reason, even if such a reverse phenomenon of the chamber pressure would take place, it is impossible to immediately cause the pressures to be equal, resulting in the problem of such a reverse phenomenon of the chamber pressures, i.e., the degradation in refrigerant gas compression function during the operation of the compressor.
In order to solve the above-described problems, an object of the present invention is to provide a pressure adjuster valve that may quickly cause the chamber pressures of the two chambers to be equal to each other with high reliability, when the chamber pressures of the two chambers are reversed, and to provide a gas compressor utilizing the pressure adjuster valve.
In order to achieve the above-mentioned objects, according to the present invention, there is provided a pressure adjuster valve having a communication passage for connecting two chambers, a truncated conical hole provided as a valve seat portion on the way of the communication passage, and a valve body provided to be movable within the communication passage and formed to be engageable with the truncated conical hole, characterized in that:
wherein when a chamber pressure within one of the chambers is lower than a chamber pressure of the other chamber, the valve body is depressed into the truncated conical hole by means of a pressure difference between the two chambers to thereby close the communication passage whereas the chamber pressures of the two chambers are reversed, the valve body is released and moved away from the truncated conical hole by means of the pressure difference between the two chambers upon the reversal to thereby open the communication passage;
the pressure adjuster valve comprises a broadening means for partially broadening a width of a fine gap between the valve body and the communication passage.
According to the present invention, there is provided a pressure adjuster valve having a communication passage for connecting two chambers, a truncated conical hole provided as a valve seat portion on the way of the communication passage, and a valve body provided to be movable within the communication passage and formed to be engageable with the truncated conical hole, characterized in that:
wherein when a chamber pressure within one of the chambers is lower than a chamber pressure of the other chamber, the valve body is depressed into the truncated conical hole by means of a pressure difference between the two chambers to thereby close the communication passage whereas the chamber pressures of the two chambers are reversed the valve body is released and moved away from the truncated conical hole by means of the pressure difference between the two chambers upon the reversal to thereby open the communication passage;
the pressure adjuster valve comprises a biasing means for normally biasing the valve body in a direction away from the truncated conical hole.
According to the present invention, there is provided a pressure adjuster valve having a communication passage for connecting two chambers, a truncated conical hole provided as a valve seat portion on the way of the communication passage, and a valve body provided to be movable within the communication passage and formed to be engageable with the truncated conical hole, characterized in that:
wherein when a chamber pressure within one of the chambers is lower than a chamber pressure of the other chamber, the valve body is depressed into the truncated conical hole by means of a pressure difference between the two chambers to thereby close the communication passage, whereas the chamber pressures of the two chambers are reversed, the valve body is released and moved away from the truncated conical hole by means of the pressure difference between the two chambers upon the reversal to thereby open the communication passage,
the pressure adjuster valve comprises a biasing means for normally biasing the valve body in a direction away from the truncated conical hole in addition to a broadening means for partially broadening a width of a fine gap between the valve body and the communication passage.
The pressure adjuster valve according to the present invention is characterized in that the broadening means broadens an upper portion of the overall fine gap.
The pressure adjuster valve according to the present invention is characterized in that the broadening means is a means for broadening widths at several positions of the fine gap.
The pressure adjuster valve according to the present invention is characterized in that the broadening means is composed of a groove formed in an inner wall of the communication passage along a moving direction of the valve body.
The pressure adjuster valve according to the present invention is characterized in that the broadening means is composed of a groove formed in an outer circumferential surface of the valve body.
The pressure adjuster valve according to the present invention is characterized in that the biasing force of the biasing means is greater than a bonding force of oil film for bonding the valve body to the truncated conical hole.
According to the present invention, there is provided a gas compressor comprising a cylinder disposed between a pair of side blocks, a rotor laterally rotatably supported inside of the cylinder through bearings provided on the pair of side blocks and a rotor shaft supported by the bearings, vanes provided to be projectable and retractable from an outer circumferential surface of the rotor toward an inner wall of the cylinder, a compression chamber formed and partitioned by the cylinder, the side blocks, the rotor and the vane, repeating changes in magnitude of volume in accordance with a rotation of the rotor and sucking and compressing refrigerant gas within a suction chamber to thereby discharge the medium to the side of a discharge chamber due to the volume change, a flow path of oil for pressurizing and feeding the oil to the side of a back pressure chamber in communication with bottom portions of the vanes through a bearing clearance of the side blocks from an oil sump of a bottom portion of the discharge chamber, and a pressure adjuster valve for causing both the pressures of the suction pressure and the back pressure chamber pressure of the refrigerant gas to be equal to each other when the suction pressure and the back pressure chamber pressure are reversed, characterized in that:
wherein the pressure adjuster valve comprises a communication passage for connecting the suction chamber and back pressure chamber, a truncated conical hole provided as a valve seat portion on the way of the communication passage, a valve body provided to be movable within the communication passage and formed to be engageable with the truncated conical hole, and a broadening means for partially broadening a width of a fine gap between the valve body and the communication passage;
when a chamber pressure within the suction chamber is lower than a chamber pressure of the back pressure chamber, the valve body is pressed into the truncated conical hole by means of a pressure difference between the two chambers to thereby close the communication passage, whereas the chamber pressures of the two chambers are reversed, the valve body is released and moved away from the truncated conical hole by means of the pressure difference between the two chambers upon the reversal to thereby open the communication passage.
According to the present invention, there is provided a gas compressor comprising a cylinder disposed between a pair of side blocks, a rotor laterally rotatably supported inside of the cylinder through bearings provided on the pair of side blocks and a rotor shaft supported by the bearings, vanes provided to be projectable and retractable from the outer circumferential surface of the rotor toward an inner wall of the cylinder, a compression chamber formed and partitioned by the cylinder, the side blocks, the rotor and the vane, repeating changes in magnitude of volume in accordance with a rotation of the rotor and sucking and compressing refrigerant gas within a suction chamber to thereby discharge the medium to the side of a discharge chamber due to the volume change, a flow path of oil for pressurizing and feeding the oil to the side of a back pressure chamber in communication with bottom portions of the vanes through a bearing clearance of the side blocks from an oil sump of a bottom portion of the discharge chamber, and a pressure adjuster valve for causing both the pressures of the suction pressure and the back pressure chamber pressure of the refrigerant gas to be equal to each other when the suction pressure and the back pressure chamber pressure are reversed,
wherein the pressure adjuster valve comprises a communication passage for connecting the suction chamber and back pressure chamber, a truncated conical hole provided as a valve seat portion on the way of the communication passage, a valve body provided to be movable within the communication passage and formed to be engageable with the truncated conical hole, and a biasing means for normally biasing the valve body in ad direction away from the truncated conical hole;
when a chamber pressure within the suction chamber is lower than a chamber pressure of the back pressure chamber, the valve body is pressed into the truncated conical hole by means of a pressure difference between the two chambers to thereby close the communication passage against a biasing force of the biasing means, whereas the chamber pressures of the two chambers are reversed, the valve body is released and moved away from the truncated conical hole by means of the pressure difference between the two chambers and the biasing force of the biasing means upon the reversal to thereby open the communication passage.
According to the present invention, there is provided a gas compressor comprising a cylinder disposed between a pair of side blocks, a rotor laterally rotatably supported inside of the cylinder through bearings provided on the pair of side blocks and a rotor shaft supported by the bearings, vanes provided to be projectable and retractable from the outer circumferential surface of the rotor toward an inner wall of the cylinder, a compression chamber formed and partitioned by the cylinder, the side blocks, the rotor and the vane, repeating changes in magnitude of volume in accordance with a rotation of the rotor and sucking and compressing refrigerant gas within a suction chamber to thereby discharge the medium to the side of a discharge chamber due to the volume change, a flow path of oil for pressurizing and feeding the oil to the side of a back pressure chamber in communication with bottom portions of the vanes through a bearing clearance of the side blocks from an oil sump of a bottom portion of the discharge chamber, and a pressure adjuster valve for causing both the pressures of the suction pressure and the back pressure chamber pressure of the refrigerant gas to be equal to each other when the suction pressure and the back pressure chamber pressure are reversed;
wherein the pressure adjuster valve comprises a communication passage for connecting the suction chamber and back pressure chamber, a truncated conical hole provided as a valve seat portion on the way of the communication passage, a valve body provided to be movable within the communication passage and formed to be engageable with the truncated conical hole, a broadening means for partially broadening a width of a fine gap between the valve body and the communication passage, and a biasing means for normally biasing the valve body in ad direction away from the truncated conical hole;
when a chamber pressure within the suction chamber is lower than a chamber pressure of the back pressure chamber, the valve body is pressed into the truncated conical hole by means of a pressure difference between the two chambers to thereby close the communication passage against a biasing force of the biasing means, whereas the chamber pressures of the two chambers are reversed, the valve body is released and moved away from the truncated conical hole by means of the pressure difference between the two chambers and the biasing force of the biasing means upon the reversal to thereby open the communication passage.
The gas compressor according to the present invention is characterized in that the broadening means broadens an upper portion of the overall fine gap.
The gas compressor according to the present invention is characterized in that the broadening means is a means for broadening widths at several positions of the fine gap.
The gas compressor according to the present invention is characterized in that the broadening means is composed of a groove formed in an inner wall of the communication passage along a moving direction of the valve body.
The gas compressor according to the present invention is characterized in that the broadening means is composed of a groove formed in an outer circumferential surface of the valve body.
The gas compressor according to the present invention is characterized in that the biasing force of the biasing means is greater than a bonding force of oil film for bonding the valve body to the truncated conical hole.
In the gas compressor having the broadening means according to the present invention, the continuity of the oil film around the valve body in the broadened portion of the fine gap is cut, and the operational response property of the valve body is enhanced while the sticking phenomenon of the valve body by the oil film is prevented;
In the gas compressor having the biasing means according to the present invention, the valve body is forcibly separated from the truncated conical hole by the biasing force of the biasing means. Thus, the sticking phenomenon of the valve body by the oil film is prevented and the operational response property of the valve body is enhanced.
Furthermore, in the gas compressor having both the broadening means and the biasing means according to the present invention, it is possible to positively prevent the sticking phenomenon of the valve body by the oil film by means of the oil film cutting effect by such a broadening means and the separation effect of the valve body by the biasing means.